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The rhenium(V) complexes [ReCl 3 ( t -BuNC)(L)(PPh 3 )] ( 1 – 3 ) were isolated by the reaction of trans -[Re III Cl 3 ( t -BuNC)(PPh 3 ) 2 ] ( t -BuNC = tert -butyl isocyanide) with the ligands H 2 L (H 2 L = aniline ( 1 ), o -phenylenediamine ( 2 ), anthranilic acid ( 3 )). In all these complexes the dianionic ligands L are coordinated monodentately as the imide. However, unexpectedly, with 2-aminophenol the complexes [Re V Cl 2 ( t -BuNC)(L)(PPh 3 ) 2 ](ReO 4 ) ( 4 ) and the novel [Re III Cl 2 ( t -BuNC)(ibq)(PPh 3 ) 2 ] ( 5 ) (ibq − = 2-iminobenzoquinonate, the two-electron oxidized form of HL − ) were identified as the products. These complexes were characterized by single crystal X-ray crystallography, 1 H NMR spectrometry, IR and electronic spectroscopy, and cyclic voltammetry. To complement the experimental data, density functional theory (DFT) and time-dependent DFT methods were used to have a deeper understanding into the molecular parameters and infrared and electronic spectra of these complexes. [ABSTRACT FROM AUTHOR]

The reaction of the rhenium(V) complex cis-[ReO2I(PPh3)2] with 2-aminothiophenol (H2atp), benzene-1,2-dithiol (H2tdt) and 2-hydroxybenzenethiol (H2otp) led to the formation of the rhenium(III) complexes [Re(Hatp)(ibsq)2]·OPPh3, [Re(sbsq)3]·OPPh3 and [Re(obsq)3]·OPPh3 (ibsq=2-iminothiobenzosemiquinonate, sbsq=1,2-dithiobenzosemiquinonate, obsq=2-hydroxothiobenzosemiquinonate) respectively. These paramagnetic complexes were characterized by single crystal X-ray crystallography, 1H NMR spectrometry, IR and electronic spectroscopy, and cyclic voltammetry. To complement the experimental data, density functional theory (DFT) and time-dependent DFT were successfully used to investigate the structural, molecular, infrared and electronic spectra of these three complexes. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of [Re(CO)5Br] with the potentially bidentate ligands N,N-dialkylbenzoylthiourea (HL1) and its N,N-diphenyl derivative (HL2) were studied. In the complex fac-[Re(CO)3(HL1)2Br] (1) the two neutral HL1 ligands are coordinated in a monodentate manner via the thiourea sulfur atom. Coordination of the monoanionic chelate L2 occurs through the neutral benzoyl oxygen atom and the anionic sulfur atom, which also acts as a bridge to the second metal centre, in the dimeric complex [Re2(CO)6(L2)2] (2). The crystal structures of 1 and 2 were determined by X-ray single crystal diffraction. UV–vis absorption spectra of the complexes show the intraligand and MLCT transitions. [Copyright &y& Elsevier]

Abstract: The reactions of 2-hydroxybenzhydrazide (salicylhydrazide; Hshz) with trans-[ReOX3L2] (X=Cl (a), Br (b); L=PPh3] in acetonitrile and acetone were studied. With a in acetonitrile, the rhenium(III) complex [ReCl2(shz)(NCCH3)L2] (1), with shz coordinated as a monodentate diazenide, was isolated. However, with b in acetonitrile, the oxorhenium(V) dimer (μ-shd) [ReOBr(OPPh3)]2 (2) was formed. The bridging ligand shd4− was formed by the condensation of two shz ligands, with the elimination of hydrazine. In acetone, the reaction of Hshz with a produced [ReOCl2(sha)L] (3), in which the bidentate Schiff base ligand sha− was formed by the condensation of shz with acetone. The spectral and X-ray crystallographic characterization of complexes 1–3 are reported. [Copyright &y& Elsevier]

Abstract: The reactions of bis(benzothiazol-2-ylethyl)sulfide (bts) and its benzimidazole analogue (btn), both with a N2S-donor atom set, with [Re(CO)5Br] and cis-[ReO2I(PPh3)2] were studied. The X-ray crystal structure of fac-[Re(CO)3(bts)Br] shows that bts acts as a bidentate NS-donor ligand, with a free uncoordinated benzothiazole group. With rhenium(V) the dimer (μ-O)2[Re2O2(btn)2]I2 was isolated, in which btn acts as a tridentate N2S chelate to each metal centre. Each oxo-bridge is unsymmetrical, with unequal Re-O distances. [Copyright &y& Elsevier]

The reaction of [ReCl 3 (MeCN)(PPh 3 ) 2 ] with 2-mercapto-orotic acid (H 2 moa) in ethanol led to the isolation of the multiply-bridged dimer ( μ -Cl)( μ -O)( μ -moa) 2 [Re III Re IV (PPh 3 )] 2 ( 1 ). The compound has a Re Re bond distance of 2.5425(7) Å with a formal bond order of 2.5. The dianionic bridging ligands moa 2 − coordinate bidentately via a neutral pyrimidine nitrogen and carboxylate oxygen to one Re ion, and monodentately through a thiolate sulfur to the second metal ion. Complex 1 was characterized by FTIR, electronic spectroscopy, cyclic voltammetry, microanalysis and single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

The reaction of cis-[ReO2I(PPh3)2] with 3-methyl-2-aminophenol (H2map) in ethanol led to the formation of trans-[Re(map)(Hmap)I(PPh3)2]I. The X-ray crystal structure shows that the ligand map is coordinated monodentately through the doubly deprotonated amino nitrogen and is therefore present as an imide. The chelate Hmap is coordinated via the neutral amino nitrogen and the singly deprotonated phenolate oxygen, which is coordinated trans to the imido nitrogen. In benzene equimolar quantities of cis-[ReO2I(PPh3)2] and 4-methyl-2-aminophenol (H2amp) produced the five-coordinate cis-[ReO2(Hamp)(PPh3)]. A twofold molar excess of 2-aminophenol (H2ap) yielded the six-coordinate [ReO(Hap)(ap)(PPh3)]. The chelate ap is coordinated through the deprotonated phenolate oxygen and the singly deprotonated amino nitrogen (amide). [Copyright &y& Elsevier]

The reaction of a twofold molar excess of 2-amino-3-methylbenzoic acid (H 3 amb) with cis -[ReO 2 I(PPh 3 ) 2 ] in ethanol led to the isolation and characterization of the six-coordinate [Re(amb)(OEt)I(PPh 3 ) 2 ] ( 1 ). The X-ray crystal structure of 1 illustrates that the trianionic ligand amb acts as a bidentate chelate via the doubly deprotonated amino nitrogen, which is present in 1 as an imide, and the deprotonated acetoxy oxygen. The Re=N bond length is 1.751(3) Å, and the Re=N-C angle [143.6(3)°] deviates considerably from linearity. [ABSTRACT FROM AUTHOR]

The reactivity of oxorhenium(V) precursors with the potentially N , N -donor ligand 2,2′-dipyridylamine (dpa) has been investigated. Reaction of a two-fold molar excess of dpa with trans -[ReO(OEt)Cl 2 (PPh 3 ) 2 ] in ethanol led to the isolation of [ReOCl 2 (OEt)(dpa)] ( 1 ). Spectroscopic measurements indicate that dpa is coordinated as a bidentate in the equatorial plane cis to the oxo group, with the ethoxide in the trans position. Treatment of trans -[ReOCl 3 (PPh 3 ) 2 ] with a tenfold molar excess of dpa in ethanol at reflux yielded the trans -dioxo complex [ReO 2 (dpa) 2 ]Cl ( 2 ), but with a twofold molar excess (μ-O)[{ReOCl 2 (dpa)} 2 ] ( 3a ) was isolated. The latter reaction with ( n -Bu 4 N)[ReOCl 4 ] as starting material in ethanol at room temperature led to a dark green product, also with the formulation (μ-O)[{ReOCl 2 (dpa)} 2 ] ( 3b ). These compounds were characterised by common spectroscopic techniques, and the crystal structures of 2 ·3H 2 O, 3a and 3b ·2DMSO were determined. The structure of 3b presents a nearly linear O=Re-O-Re=O group, with the two [ReOCl 2 (dpa)] halves of the dimer rotated by 180.0° about the Re-O-Re fragment away from an eclipsed conformation. In 3a , the two halves are only rotated by 61.4°. [ABSTRACT FROM AUTHOR]

The reaction of trans -[ReOBr 3 (PPh 3 ) 2 ] with 5-amino-orotic acid (H 2 aoa) in ethanol led to the isolation of the triply-bridged dimer [Re IV 2 (μ-O)(μ-Br)(μ-aoa)Br(OEt) 2 (PPh 3 ) 2 ] ( 1 ). The compound has a Re Re bond distance of 2.5526(4) Å. The dianionic bridging ligand aoa coordinates bidentately via an amido nitrogen and carboxylate oxygen to one Re ion, and monodentately through a neutral carbonylic oxygen to the second metal ion. Density functional theory (DFT) calculation shows that the presence of the rhenium atoms leads to a noncollinear spin phase arrangement for the bridging atoms. [ABSTRACT FROM AUTHOR]

Abstract: The products of the reactions of [Re(CO)5Cl] with 1-(benzothiazol-2-ylidene)-3-methylthiourea (Hmbt) and bis{1,2-(benzothiazol-2-ylidene)}thiourea (Hdbt) were studied. The X-ray crystal structure of (μ-mbt)2[Re(CO)3]2 shows that bridging between the two metal centres occurs via the two thiolic sulfur atoms of the two mbt ligands. One mbt ligand is also coordinated via a benzothiazole nitrogen atom to a rhenium(I) atom, with the second mbt ligand attached to the metal via a thiourea imino nitrogen. In the complex (μ-dbt)2[Re(CO)3]2, each dbt ligand bridges two metal centres in a ‘2+1’ manner, with each rhenium atom in a N2SC3 donor atom set. [Copyright &y& Elsevier]

Abstract: The reactions of the potentially tridentate Schiff bases 2-[(2-hydroxyphenyl)iminomethyl]phenol (H2ono) and 2-(2-aminobenzylideneimino)phenol (H3onn) with trans-[ReOBr3(PPh3)2] were studied, and the complexes [ReIIIBr(PPh3)2(ono)] (1) and [ReVBr(PPh3)2(onn)]Br (2) were isolated. In 1 ono acts as a dianionic tridentate ligand, and in 2 onn is coordinated as a tridentate trianionic imido-imino-phenolate. The complex [ReI(CO)3(ons)(Hno)] was isolated from the reaction of [Re(CO)5Br] with 2-[(2-methylthio)benzylideneimino]phenol (Hons; Hno=2-aminophenol), with ons coordinated as a bidentate chelate with a free SCH3 group. These complexes were characterized by X-ray crystallography, NMR and IR spectroscopy. [Copyright &y& Elsevier]

Abstract: The seven-coordinate rhenium(III) complex cation [ReIII(dhp)(PPh3)2]+ was isolated as the iodide salt from the reaction of cis-[RevO2I(PPh3)2] with 2,6-bis(2-hydroxyphenyliminomethyl)pyridine (H2dhp) in ethanol. In the complex fac-[Re(CO)3(H2dhp)Br], prepared from [Re(CO)5Br] and H2dhp in toluene, the H2dhp ligand acts as a neutral bidentate N,N-donor chelate. The complexes were characterized by elemental analysis, infrared and 1H NMR spectroscopy and X-ray crystallography. [Copyright &y& Elsevier]